Differential mechanism



. March 1 1927` F. M, LEWIS DIFFERENTIAL MECHANIsM l Filed May 11, 1925 s sheets-sheet 1 A il f Il w Maich 1 1927. 1,619,141

F. M. LEWIS DIFFERENTIAL MacHANrsM Filed May 1.1, 1925 Y A v:svsheets-sinnev Marh l 1927.

F. M. LEwls DIFFERENTIAL MECHANISM Filed May 11'; 1925 s sheets-sheet s evno-nT /VPMQ Patented Mar. 1, 1927.

fILEW-IS, OF SCHICAGD, 'ILIEEN'OYIS.

.Application .filed May '11, 1925. vSerial No, .29,2'15.

This invention relatesto differential mechanism designed mainly, .but not exclusively, for .use on automobiles, trucks, and other motor vehicles, and .has referencey more .par-

ticular'ly-to a mechanism ,oft thegeneral type disclosed .in Vformer Letters Patent oft the UnitedStates heretofore granted ito me No.

1,292,818, dated January ;28, 1,9119 andNo.-

1,430,744 :dated iQctoberB, .1922, :and characterized by the provision .of :a jpair ot dri-venclutch .members 'fast on the inner ends of the `axle sections, .a pair Yot laterally shiftable fdriving :clutch members .between `said driven `clutch members, a rotatable housing enclosing said dnivin-g and driven Clutch members, `and a driver .having the ,general formfot ra spider .mounted :in said .rotatable housing and having radial studs in driving engagement v.with the inner sides oft said shi-:ttabie clutch members.

.In 'one ,knownfform o -diferential mechanismfof this general type, eXempl-ilied in Letters Patent to Manifold No. 1,240,748, September d8, 19.17 and A.to :Cartwright No. 1,477,310, December lil., 1928, .the .two llaterally shitta'blc v'driving `clutch .members .are connected .by aplurality `of ,pivoted Ilin-ks located lbetween adjacent Aspider arms of the driver .and under normal dri-.ving Yconditions lying gparaillel with ythe axle. When .one of the wheels overruns the other, as .for instance the -outer wheel .in 'turning Vthe Ycorner or traveling xonfacurved path, the Adriven clutch member pertaining .to fsuch Afaster running wheeltends to drive its cofoperating driving -clultch member .at .a jgreater speed .than that Ao'f the :driving -clutc'h rmember on ythe otherside; andthisswings the .links .to a

,position more or less .inclined to the axle, fpl'acingsaid links -under tension, and the .pull of the tlatter then draws the .driving -clutch member .of the 'overrnnning wheel out :off `clutch 'engage-ment with its .co-.operating driwen clutch member., permitting 'the `overrunning wheel to ithen tur-n freely.

Inthe known 'construct-ions otr-this type, however, 'a single l-pair, -or Vtwo pairs, of links ,have ibeen employed for disengaging the driving clutch -mem'ber `oi thexoverrunning -wheelin bothdirections of rotation of the latten; inother words, in .both `for-ward =and backward driving. Vlhs necessitates 'an arrangement Lof vthe Llinks wherein Aduring .normalV torward or {rearward dri-ving, when r both `driving clutch members are engaged,

the links lie substantially parallel with the axle. This .involves a very considerable swinging movement oit 'thelin'ks `rin order to effect disengage-niient, .-since, manifestly, Aas the link swings from a position parallel to the axle itoward .a Aposition at v`right angles to the latterthe inward travel of the swinging.e1id of the link :is lat iirst very slight, and increases to its maximum .as it` approaches the right angle position.

One objectv of my `present invention is to provide an 'improved differential mechanism ofthe last referred to 'type wherein, however, a separationof 'the driving and driven Vclutch members, ot fthe overrunning wheel maybe equally edected through a comparatively small swinging movementrof'thellinks To do this, I-emplo-ytwo ,sets of links, .one for disengaging the right hand-clutch during forward travel and the left 'hand clutch duringfbaclmvard ftravel, andthe other "for di sengag'ing 'the 'lett hand `clutch during fiorward travel and the right hand c'lutch .during backward travel; and these 'links are so disposed that when v'both clutches are engage-d, theylie at 'largeangles tothe axis oi he axle; and in order that, when Aone set oi links lis operative, the other set may not interiere with the operation, 'I .mount 'at least .one pivot studof eachV link in a -Ibearing in the driving clutch member which aords sufficient lost motion 'to .enable fthe idle set o .links lto conform Lto, and avoid interference with, fthe .action of `the active set of links.'

Another object of my invention is 'to ,provide, in Yassociation with the improved link arrangement above referred to, an arrangement or" driving-and driven clutch .members suchthat when the driving clutch members are fully .engaged with .their vrespective driven .clutch members, the space between :them will 'be the minimum Vrequired lto effyiect complete separation oi one only oi the drivinggclntch anembers at a time "from its co-:opierating driven clutch member, Ywhei-eby .itis possible toset the links -at an angle such .that a very .slight swing of the vlinks effects such separation.

Another practicaliessential in di'ierentias olif this type is that -the -driven clutch memkbers .shall .be `so mounted that they cannot, lunderany conditions encountered in service, become displaced 'to-ward each other, .since .this .would manifestly interfere with the proper functioning of the driving clutch mem- .bers vto ,free the zdriven clutch members durnsl ing the overrunning travel of the latter. This requisite I secure by providing a construction wherein either the inner ends of the axle sections on which the driven clutch members are lixedly keyed, or the inner ends oi thehubs of the driven clutch members or both, are in actual opposing contact; or the hub of the driving spider serves to space thedriven clutch members. i

Other objects and attendant advantages of the invention will be apparent to persons skilled in the art as the saine becomes better understood by reference to the following description, taken in connection with the accompanying drawings wherein I have illustrated two practical forms and applications of the principle of the invention, and in which- Fig. 1 is an axial section of my improved differential mechanism; Fig. 2 is a central transverse section through the same on the line 2 2 ot Fig. 1;

Fig. 3 is also an axial section taken in a different plane from that of Fig. 1, on the line 3--3 ot' Fig. 2;

Fig. 4 is an elevation ol the same; with the rotatable housing omitted` showing the parts in normal running position wherein both axle sections are driven. the direction of drive being indicated by arrows;

Fig. 5 is a view similar to Fig. el, but showlng the relative positions ot the parts when the right hand axle is running at a greater speed than the left hand axle, and the right hand driving clutch member has been disengaged;

Fig. 6 is a view similar to Figs. Il and 5, showing the right hand clutch member disengaged when running in the opposite direction to that indicated in Figs. l and 5;

Figs. and S are enlarged longitudinal sections through the links and their `bearings taken on the lines 7-7` and 8 8 respectively of Fig. 5;

Fig. 9 is a perspective detail ot one of the links;

Fig. 1() is a housing;

Figs. 11 and 12 are views similar to Fig.

perspective detail ci a spring `4, showing an application oi the invention to the three-arm spider and axle gearsof the Ford type; the parts appearing m nor- `mal running position m both views;

Fig.` 13 is a view similar to Fig. 12; but showing the relative positions of the parts when the right hand axle is overrunning the left hand axle; and t Fig. 14 is a central transverse section on the line lt--lt of Fig. 11.

Referring to the drawings; and describing lirst the form of the invention illustrated in Figs. 1 to 10 inclusive, 15 and 16 designate (zo-operating halves of `a rotatable housing, united by machine screws 17 (Fig.

`3) and enclosing the principal co-`operating parts ofthe differential gear. Into the opposite ends of this housing are entered the two axle sections 1S and 19, on which are ke'ved the hubs 2() and 2l ot a pair ot outer driven clutch members and E23, which latter` are 'l'ormed on their inner sides with radial clutch teeth 31. ln the construction shown the outer ends o'lE the hubs 2O and 21 constitute bearings for the rotatable housing. In lieu of the plain bearings herein shown merely tor purposes or' illustration; the customanv roller bearings may. on" course, be employed. liv reterenee to Fig. 1 it will be observed that the inner ends of the sha-tts it, and 10 and also the inner ends otthe hubs 2O and :2l meet in direct contact with each other.

On the inner meeting portions oli the hubs :2O and 2l is rotatably mounted the relativelv long hub olf a driver spider', the hub 25 cti-operating with the outer end bearings ot' the hubs 2O and 2l to maintain the latter .in accurate axial alinement. In the construction shown in Figs. 1 and 2 t-he driver spider has tour radial arms ninety degrees apart, each arm comprising an inner squared pertion 26 :termed with beveled corners 2T con stituting cams, and an outer round portion 28; which latter, as clearliT shown in Figs. l and il. is rigidli;Y mounted in and between the mating sections 15 and 1G ol the rotatable housing.

Between the driver spider and the driven clutch members Q2 and 23 are located a pair ot driving clutch men'ibers 29 and Each ot these members takes the lorm ol" an annulus, the inner periphery otl which has a running and slidingl tit on the hub 25 ot' the spider. The outer periphery is flattened between adjacent spokes ot. the spider, as shown at `31 in Fig Q to provide space and seats for the links hereinafiter described. On the outer side ot' each of these driving clutch men bers 29 and 30 is a ring of radial clutch. teeth 3:2 adapted to inter-lit and co-operate with the clutch teeth 2li; ot' the driven members 22 and 23. On the inner side of the shittable clutch members 29 and 30 are formed radial recesses having inclined sides 355; clearly shown in Fig. the inclination ot the sides 33 corresponding to that of the bevels or cams 2T on the spider arms or spokes 26. clearly shown in Figs. 1, Ll; and 5, `the mating` recesses on the two shittable members en'lbrace the inner squared portions of the arms ot the spider; with a limited amount ot both longitudinal and lateral clearance. By reference to Figs. and (l it; will be observed that the thickness 'ot the two shittable clutch memliers Q9 and l0 is such that their inner edges will come into contact with each other before both ot said members can be simultaneously disengaged :trom their respective driven clutch members 29 and 23. In other words, both clutch members cannot simultaneously be disengaged or unclutehed. Y

Pivotally connecting diametrically opposite flattened peripheral portions 3l of the two driving clutch members 29 and 30 area pair of links 34; and similarly connecting the intermediate diametrically opposite flattened eri'pheral portions 3l are another pair or' inks 35. The links 34 and 35 are all alike, and'. by reference to Fig.A 9 it will be observed that each link is formed on its ends with a pair ofround studs 36 disposed at a right angleto the body of the link, which studs are ente-red in sockets 37 and 38 formed in the dri-ving clutch members 29- and 301' All of these links are disposed at a steep angle to the axis of the axle: and it will be observed by reference tvo-Fig. 5 that the links 34 and 35 are oppositely inclined. It willy also beI seen by reference to Figs. 7 and 8 that, 1n the case of' each link, one of thc'- sockets', such' as 37, is round and affords only a turning it to the stud 36 of the link, while the other socket, suoli as 38, is slightly oblong ifnr the direction of the link, and permitsV a small amount of play of the stud 36 therein. At the overrunning of the right hand wheel in a. forward' direction, such as is n indicated in Fig. 5, the linksv 34 are active to retract the driving clutch member from the driven clutch member 23 and the links are idle.' At the overrunning of the right hand wheel in a rearward direction, the linksr 35' are' active and the lin-ks 34 idle. At the overru-iming or' the left hand wheel in aforward direction the links 35 are active and the links 3.4 idle, and at the overrunn-ing oi' the left hand wheel in a rearward direction the links 34 are active 'and' the links 3'5 are id'le. Iny all ofl thesev cases, the slightly elonmg movement ofv the idle links topermit, and

not interfere with. the inward or separati-ng movement of the driving' clutch member on thek side on which the overrunning occurs.

lIn the inner face of one or' the driving clutch members 29 and 30 (the member 30 as herein shown) are formed a grou-p ot holes or sockets 39 (F 3) in which are slidably mounted thimbles 40, onev of' which is shown in isolated detail in Fig. 10; and within these thimbl'es are coi-l com-pression Vsprings 41 that abut at one end against the bottoms of the sockets 39 and at their other ends against the bottoms oi? the thimbles 40, press ing the latter against the opposed face of the other driving` clutch member. These springsserve to start andE urge the driving clutch members 29 and 30 apart and' into drivingengagement` with their eo-operating driven clutch members22 and '23. During normat running in a forward or rearward direct-ion, when both' driving clutch members are engaged with their respective driven clutch members, the thrust of the cams27 of gated socket 38 permits the necessary swing-v the spider'l armson `the inclined sides 33V oi the recesses iny the shittable; clutch members acts to press said shi-ftableclutch members outwardly, and maintain them in clutch engagement with said driven members.

Cotter pins 42l formed with round headsencircling the projecting ends of they tlrimblesy extend vthrough centralv holes 43? in the links 34 and 35 and serve to hold the latter in place without interterring with the free swinging movement of sai-dv links.

The exact degree of inclination of the links 34 and 35 to the axis of the axle* is not es'- sential", but preferably said links are inclined at an angle somewhat greater kthan: forty-tive degrees; and I have found inpractice that the most satisfactory results are secured when the links are disposed at an angle such that the longitudinal median axis 'of the link is substantially normal tothe inc-lined surfaces 27 and 33 of the spider arm and recess of the driving clutchmember which are separated during the inward swing of the active link. Manifestly, the clearanceafforded by the slightly oblong socket 38 might be distributed through both sockets of each link, but, from amanufacturing viewpoint, it is more simply and' economically provided inoneA socket only of the pair.

In Figures 11 to 14 inclusive I have illlustrated an application of the principle of the invention to a known form of standard dif-l erenti al employing a driving spider having three arms or spo-kes disposedr one hundredand twenty degrees apart, such as the Ford. In these views` 44 and 45 designate the regular standard rear axle bevel gears employed with the standard differential, this latter' including a divided differential housing, one member of whichy is shown at 46 in Fig. 14 united by screws 47, attached to and drivenI by the diderential master gear (not shown). This di'iieren-tia-l lrousing 46 is' formed with three radialv seats 48 which, in the standard construction, constitute bearings for theV stems or spindles et the differential pinions.` For the regular differential spider and pinions I substitute the tl'iree-arm spider designated as an entirety by 49; this member' being similar in all respects tothe four-erm spider previously described and shown in: Figs. l and 2, except that it is formed with three arms one hundred and twenty degrees apart instead of four arms ninety degrees apart. C'o-operatingwith this spider are the laterally shiitable driving clutch-.members 29 and 30 formed with three periphera-lly flattened portions 3l which, since they are formed on one hundred and twenty degree sectors, may be of greater length than the corresponding flattened portions 3l illustrated in Fig. 2. On each ofl these flattened portions 31 are mounteda pair of oppositely inclined links 34 and 35 that correspond functionally with the links 34 and 35 previously described and arc mounted in the same manner upon and in the driving clutch members Q9 and 50. This construction, therefore, provides in a differential mechanism en'iploying a three-arm spider, two independently acting sets ot links vtor ellecting the disengagement ot' the driving clutch members during over-running of either wheel when traveling either in a forward or a rearward direction.

It is believed that thc structural features, mode or principle ot' action, and practical advantages ol the invention will be clear to persons skilled in the art from the foregoing description without turther elaboration. lit will be manit'est that by providing two iudependentljv acting sets of links, one set tunetioning during overrunning ol a wheel in one direction and the other during overrunning of the same wheel in the opposite direction it is possible to dispose these links at such an angle to the axis oi `the axle that but a very limited swinging movement ot the link and a veriT limited relative rotar)l movement of the two driving clutch nieiribers are required to ell'ect the disconnection ot the driving clutch member trom the driven clutch member. hence making it unnecessary to provide additional movement limiting de` vicesbetween the two driving clutch members, the links themselves also performing this function. Hence it will be seen that mv present invention provides angular-lv movable means connecting the two driving clutch members through the agency ot which either of said driving clutch members is disengaged trom its driven clutch member with a minimmn` of back-lash whenever the axle carrying the driven clutch .member overruns the other axle in either direction. Moreover, the described structure lends itself to economy of structure and maintenance, since the manufacture o't' the links and the socketing of the driving clutch members to receive them is simple and ot low cost, and said links are easily and cheaply replaced in case of breakage.

1While I have herein shown and described certain practical and workable embodiments ot' the invention, it is manifest that the operative principle thereof might be embodied in other more or less specifically diiiierent forms; and hence I do not limit the invention to the particular embodiments herein disclosed, but reserve all such variations and modilications as fall within the spirit and purview i ot the appended claims.

I claim- 'Lln a dillerential mechanisl'n. the combination ot a rotatable housing, axle sections entered within the opposite ends ol said housing, driven clutch members :tast on said axle sections, shiltable clutch members between said driven members, a driver connected to said housing and having portions thereoi drivingly engaged with 4said shiftahle members, means urgingsaid shiftable members outwardly into clutch engagement with said driven members, angularly movable means connecting said shiltable members operating to etiect disengagement oli' either ot said shiftable members from its co-operating driven clutch member when one shiftable member overruns theother in one direction, and other angnlarly movable means connectingl said shittable members operating to etiect disengagement ojt either ot said shittable members .trom its cti-operating driven clutch member when one shiftable member overruns the other in the. opposite direction.

E2. In a differential mechanism, the combination oi' a rotatable housing,` axle sections entered within thc opposite ends of said housing, driven clutch members fast on said arde sections, shi't'table clutch members between said driven members, a driver connected to said housing and having portions thereof drivinglv engaged with said shiftablc members, means urging said shift-able members out vfardly into clutch engagement with said driven members, a set of links inclined in one direction to the axis ot said axle sections pivotally connecting said shittable members and operating to effect inward clutch disengaging movement ot either of said shiltable members when one shittable member overruns the other in one direction, and another set ot links inclined in the opposite direction to the axis ol said axle sections pivotally connecting said shittable mem` bers and operating to etlect inward clutch disengaging niovement ot either of said shittable members when one shiftable member overruns the other in the opposite direction.

Il. ln a dilierential mechanism, the combination ot a rotatable housing, axle sections entered within the opposite ends ot' said housing, driven clutch members fast on said axle sections, shittable clutch members between said driven members, a driver connected to said housing and having portions thereot drivinglyY engaged with said shii'table members, means urging said shiltable meinbcrs, outwardly into clutch engagement with said driven members, a set ot' links inclined in one direction at an angle exceeding `forty-live degrees to the axis of said axle sections pivotally connecting the peripheries ol.r said shittablc members and operating to eliiectinward clutch disengaging movement ot' either ot the latter when one shiftable member overruns the other in one direction, and another set ot linksl inclined in thc opposite direction at an angle exceeding fortytivc degrees to the axis o t said axle sections pivotall)Y connecting the peripheries ot said shit'table members, in alternating arrangement with said First-named set ol. links, and operating to effect inward clutch disengaging movement of either ot' said shiftable members when one shiftable member over.

runs the other in the opposite direction.

4. A specific embodiment of claim 3 wherein the links are formed with studs pivotally engaged with sockets in the shiftable clutch members, and the studs have sutlicient lost motion in their sockets to permit idle inward swing of one set of links during active inward swing of theother set.

5. In combination with the mechanism defined in claim 4, means for locking the links on the peripheries of the shittable clutch members with the studs of the links engaged with their respective sockets.

6. In a differential mechanism, the combination of a rotatable housing, axle sections entered within the opposite ends of said housing, driven clutch members fast on said axle sections, shiftable clutch members between said driven membersformed with recesses in their adjacent sides, one of said shiftable clutch-members being also formed with holes in its inner side, a spider connected to said housing having radial arms disposed within mating recesses of. said shift-v -able members, apertured links pivotally connecting said shiftable members to each other and operating to effect a relative inward sliding movement ot said shiftable members under a relative turning movement thereof, thimbles slidably mounted in said holes, compression springs in said thimbles acting to pressthe latter against the opposed face of the other shiftable clutch member, and cotter pins having eyes encircling said thimbles and legs passed through the apertures of said links and bent over the outer sides of t-he latter.

7. In adii'erential mechanism, the combination of a rotatable housing, axle sections entered within the opposite ends of said housing, driven clutch members fast on said axle sections, laterally slidable clutch members between said driven clutch members formed with mating recesses in their adjacent sides, the space between said driven clutch members being suoli that both of said laterally slidable clutch members cannot become simultaneously disengaged from said driven clutch members, a spider connected to said housing` and having radial arms thereof disposed within mating recesses of said slidable members, means normally urging said slidable members voutwardly into clutch engagement with said driven members, and a group of links inclined at an angle exceeding forty-live degrees to the axis of rotation of said axle sections pivotally connected to andk spaced around the peripheries of said slidable members, whereby said links act to disengage said slidable members from their respective driven members under slight relative rotation of said slidable members.

8. A specic embodiment of claim 7 wherein means are provided Vfor locking said driven clutch members against inward displacement toward each other.

9. In a differential mechanism, the combination of a rotatable housing, axle sections entered within the opposite ends of said housing, driven clutch members fast on said axle sections, laterally shiftable clutch members between said driven clutch members formed with mating recesses in their adjacent sides and with seats in their peripheries, a driver connected to said housing and having portions thereof disposed within the mating recesses of said shit'table members, compression springs between said shittable members normally urging the latter outwardly into clutch engagement with said driven members, and a group of connecting links spaced around the peripheries of said shiftable members and each Jformed with end portions pivotally engaged with a pair of opposed seats in said shiftab-le clutch members, adjacent links being oppositely inclined to the axisof rotation of said axle sections.

l0. In a differential mechanism, the combination of a rotatable housing, axle sections entered within the opposite ends of said housing, driven clutch members fast on said axle sections, laterally shiftable clutch members between said driven members formed with recesses in their adjacent sides, a driver connected to said housing and having radial studs disposed within mating recesses of said shiftable members, co-oper ating cam means on said driver and said shiftable members for forcing the latter outwardly, and maintaining them in clutch engagement with said driven members, springs between and normally urging said shiftable members towards said driven members, and two'sets of connecting links grouped in alternating relation around the peripheries of said shitable members and pivotally connecting the latter with capacity for a limited degree of lost motion, the links of the two groups being oppositely inclined to the axis of rotation of said axlesections and `functioning under differential movements of said axle sections in opposite direct-ions, respectively.

FRANK M. LElVI-S. 

